1. Field of the Invention
The present invention relates to a structure of an oil pan of an internal combustion engine.
2. Description of the Related Art
Conventionally, as a technique for improving a mounting rigidity and a mounting stability of an oil pump to an engine, for example, there has been proposed a technique disclosed in Japanese Unexamined Patent Publication No. 2002-339712.
In the conventional technique, an oil pump is mounted to a bearing cap provided in a lower surface of a cylinder block by a bolt, as well as to the cylinder block, whereby a mounting rigidity and a mounting stability are improved. However, in the conventional structure, since the oil pump is mounted as an independent structure to the cylinder block, there has been a problem that the weight increases.
Further, because an oil pump attachment portion is necessary to be provided in a cylinder block, there has been problems, such as problems that the configuration is complicated, and a casting property of the cylinder block is deteriorated.